Photographic emulsions and solutions containing thioglycolic acid derivatives



Patented Oct. 27, 1953 PHOTOGRAPHIC EMULSION S AND SOLU- TIONSCONTAINING THIOGLYCOLIC ACID DERIVATIVES Wesley G. Lowe and Marcelle E.Hamshire, Rochester, N. Y., assignors to Eastman Kodak Company,Rochester, N. Y., a corporation of New Jersey No Drawing. ApplicationNovember 5, 1949, Serial No. 125,846

7 Claims. 1

This invention relates to photography and particularly to a method ofpreventing image degradation of an exposed silver halide emulsion duringprocessing.

Silver halide emulsions are frequently subject to image degradationduring processing, that is, during development, fixing, washing, toning,etc, and during the moist heat to which they are sub jected on drying aswhen prints are subjected to ferrotyping or hot-glazing. Thisdeterioration of the image frequently manifests itself as plumming orbronzing of the image during ferrotyping. Other types of imagedegradation are also encountered as will become apparent hereinafter.

It is accordingly an object of our invention to provide a method forpreventing image degradation of an exposed silver halide emulsion duringprocessing. A further object is to provide a method for preventingplumming of exposed and developed photographic prints duringferrotyping. A further object is to provide silver halide emulsionscontaining agents which reduce or prevent plumming or other types ofimage degradation. A still further object is to provide a method forpreventing or reducing various types of image deterioration duringprocessing of an exposed silver halide layer. Other objects will appearfrom the following description of our invention.

These objects are accomplished by performing one or more of the steps ofdeveloping, fixing, washing and drying an exposed silver halide emulsionin the presence of a thioglycolic acid amide derivative of the followingformula:

where R is any of various aryl, heterocyolic, acyl or amino groups orthe acylated derivatives of these compounds. The thioglycolic acidderivatives may be present in any one or more of the processing baths ormay be incorporated in the sensitive emulsion layer prior to exposure ormay be incorporated in an overcoating or backing layer of the sensitivematerial.

The following thioglycollic acid derivatives exemplify those which maybeused according to our invention.

1. 4,6 dichloro methyl-Z-m-thioglycolylamino benzoylaminophenol 2. 2hydroxy-3,5-dichloro 4 methylthioglycolic anilide 3. 2 hydroxy 5chlorothioglycolic anilide 4. 2,4,6-trichloro-5-thioglycolylamino phenol5. p thioglycolylamino w.- cyanoacetophenone 6. Thioglycolic anilide 7.2 thioglycolylamino- 4 methyl phenol 2 9. 2 hydroxy 4 thioglycolylaminodiphenyl 1 10. 2 thioglycolylamino phenol 11. 2 (pthioglycolylaminophenylacetamino) 4,6 dichloro 5 methyl phenolNHzNHCOCHzSI-I 26. Thioglycolic 2,6 dihydroxy anilide When incorporatedin silver halide emulsions. these compounds are preferably used in agelatino silver chloride emulsion or a silver chloride emulsioncontaining small amounts of bromide or iodide. Silver halide emulsionsin which the carrier is-polyvinyl alcohol or hydrolyzed celluloseacetate may also be used. When. the thioglycolic derivatives areincorporated in the emulsion, they should be used in amounts of fromabout 2.5 to 25 grams per unit of silver halide formed from 1000 gramsof silver nitrate. The same concentration of the agents should bepresent in the emulsion when the agents are added by bathing theemulsion in a solution con taining them. When the emulsion layer isbathed in a solution of the compound, the solution may contain up toabout 5% of the com pound.

Not all of the compounds used according to our invention are equallyeffective for preventing or reducing all types of image degradation,although the listed compounds have been found to have some value in mostcases. For preventing plumming, that is, loss of reflection density ortone change on hot ferrotyping of photographic prints, all of thespecific compounds listed above are effective. The acylated derivativesof these compounds are less effective in general, although the followingacylated compounds have been found to be very satisfactory inantiplumming action.

4,6 dichloro 5 methyl 2 m acetyl thioglycolylaminobenzoylaminophenol,

5-acetylthioglycolylamino 1-naphthol,

2- (acetyl thioglycolylamino) benzothlazole.

A further use of our compounds is in image protecting action, that is,stabilization of the developed image against chemical attack by suchreagents as dilute cyanide or sodium thiosulfate or ammonium thiosulfatesolutions such as used in fixing baths. In general, all of the compoundslisted above are suitable for this purpose.

A further use of our compounds is for contrast increasing, desensitizingand stabilizing action, especially where the compounds are incorporatedin the sensitive emulsion layer. Compounds '7, 8, 18,23, 24 and26 areespecially suitable for this purpose.

Compound 25 is very effective for desensitizing and stabilizing actionwithout raising contrast when the compound is incorporated in theemulsion.

Compound is also efi'ective in preventing hypo drag that is, erratictone changes in the print when placed into hypo without adequate washingafter development. A still further use of our compounds is in coldtoning, that is, in producing blue-black tones upon processing theemulsion layer. ilompcunds 16, 19, 20, 21, 22

and 23 are especially suitable for this purpose as are the followingacetylated compounds:

7 2- acetylthioglycolylamido benzothiazole5acetylthioglycolylaminotetrazole 2-acetylthioglycolylaminopyrimidineAcetothioglycolyl-4-cyanoamide We are aware that thioglycolic anilideshave been used in photographic emulsions as described,

for example, in Weissberger, Kibler and Young U. S. Patent 2,448,939. Inthat case, however, the compound were used for color-forming purposesand were added to the emulsion in much larger amounts than are usedaccording to the present invention. No image degradation prevention wassought or obtained inv the Weiss berger, Kibler-and Young process withthe large.

amount of thioglycolic compound used. Since the silver is usuallyremoved in a color process, silver is not present after processing andduring ferrotyping so that no image protecting action would be requiredor obtained.

We claim 1. The method of preventing image degradation of an exposedsilver halide emulsion during processing, which comprises developing,fixing, washin and drying said emulsion, and performing at least one ofthe steps of developing, fixing,

washing and drying said emulsion in the presence in said emulsion offrom 2.5 grams to 25 grams per unit of silver halide'formed from 1000grams of silver nitrate, of a compound selected from those compoundshaving the formula an appreciable amount but less than 5%, of a compoundhaving the general formula amqncocmsn where R'is an aryl group, andprocessing said exposed emulsion in said bath.

3. The method of preventing image degradation of an exposedsilver halideemulsion during processing, Which comprises developing, fixing, Washingand drying said emulsion, and incorporating in at least one of thedeveloping, fixing and washing baths used to' process said emulsion, anappreciable amount but less than 5%, of a compound having the generalformula where R is a heterocyclic group, and processing said exposedemulsion in said bath.

- 4. The method of preventing image degradation of an exposed silverhalide emulsion durin processing, which comprises developing, fixing,washing and drying said emulsion, and incorporating in at least one ofthe developing, fixing and washing baths used to process said emulsion,an appreciable amount but less than 5%, of a com pound having thegeneral formula where R is an acyl radical, and processing said exposedemulsion in said bath.

5. A photographic silver halide emulsion containing frdm 2.5' to 25grams per unit of silver halide formed from 1000 grams of silvernitrate, of a compound selected from those compounds having the formulawhere R is selected from the class consisting of aryl, heterocyclic andacyl groups, and the acetylated derivatives of said compounds.

r 6. A photographic silver halide emulsion containing from 2.5 to 25grams per unit of silver halide formed from 1000 grams of silvernitrate, of a thioglycolylamino heterocyclic compound.

'7. A photographic silver halide emulsion containing from 2.5 to 25grams per unit of silver halide formed from 1000 grams of silvernitrate, of a compound selected from the group consisting of 4,6dichloro 5 methyl 2 m thioglycolylaminobenzoylaminophenol, 2 hydroxy-3,5 dichloro 4- methylthioglycolic anilide, 2- hydroxy 5chlorothioglyeolic anilide, 2,4,6- trichloro 5 thioglycolylamino phenol,p e thicglycolylamino w cyanoacetophenone, thioglycolic anilide, 2thioglycolylamino 4 methyl phenol, 2 thioglycolylamino 5 methyl phenol,2 hydroxy 4 thioglycolylamino diphenyl, 2 thioglycolylamino phenol, 2'(p thicglycolylaminophenyl-acetamino)' 4,6 dichloro- 5 methyl phenol, 4nitrothioglycolyl anilide, 2,4 dichlorothioglycolyl anilide,thioglycolyl-4- iodo anilide, thioglycolio 4 sulfamido anilide,

thioglycolic 4 cyanoanilide, thioglycolic 2,5-

dichloroanilide, 5-thioglycolylamino-l-naphthol, 2(thioglycolylamino)benzothiazole, 5 'thioglycolylaminotetrazole, 2thioglycolylaminopyrimidine, 5 thioglycolylamino 1,2,4 triazole,thioglycolylurea, thioglycolic-w-aminocapramid andthioglycolic-2,6-dihydroxy anilide.

WESLEY G. LOWE. MARCELLE E. HAMSHIRE;

References Cited in the file of this patent 1' Great Britain o es, 1949

1. THE METHOD OF PREVENTING IMAGE DEGRADATION OF AN EXPOSED SILVERHALIDE EMULSION DURING PROCESSING, WHICH COMPRISES DEVELOPING, FIXING,WASHING AN DRYING SAID EMULSION, AND PERFORMING AT LEAST ONE OF THESTEPS OF DEVELOPING, FIXING, WASHING AND DRYING SAID EMULSION IN THEPRESENCE IN SAID EMULSION OF FROM 2.5 GRAMS TO 25 GRAMS PER UNIT OFSILVER HALIDE FORMED FROM 1000 GRAMS OF SILVER NITRATE, OF A COMPOUNDSELECTED FROM THE THOSE COMPOUNDS HAVING THE FORMULA